Induced drag of an aircraft wing may be described as the aerodynamic drag that is generated due to the redirection of air over the wing as the wing moves through the air. The redirection of the air may include a spanwise flow of air along the underside of the wing in a generally outboard direction toward the wing tip. When the spanwise flow of air reaches the wing tip, the air flows upwardly over the wing tip and joins a chordwise flow of air moving over the top of the wing. The joining of the spanwise flow of air with the chordwise flow of air results in the formation of wing tip vortices.
The wing tip vortices are fed by other vortices that are shed as downwash along the trailing edge of the wing. The wing tip vortices and the downwash of trailing edge vortices cause the wing lift to be inclined in a slightly aftward direction. The slightly aftward inclination of the wing lift may also be described as a reduction in the effective angle of attack of the wing, and may result in a reduction in the payload capacity of the aircraft and/or a decrease in the range and/or fuel efficiency of the aircraft.
As can be seen, there exists a need in the art for a wing tip configuration that reduces the amount of induced drag generated by a wing.